The heating, ventilating and air conditioning (HVAC) requirements of some buildings are provided by multiple HVAC systems. Some such systems service disjoint portions of a conditioned space within the building, and may be essentially independent from each other. Thus, each system may include a controller, an indoor unit (e.g. including a furnace and blower) and an outdoor unit (e.g. including a compressor and fan). Typically, each controller operates to heat or cool its associated space based on a thermal load and a temperature setpoint associated with that space without regard for operation of the other independent HVAC systems.